I installed El Capitan on my work machine and it fixed a bug where my shiny new Philips 4K monitor wouldn't wake up from sleep. So yeah! I made sure to update/upgrade my Homebrew beforehand, and had no troubles there at all. About the only minor annoyances were:

. My old, free, perfectly functioning iStats Menu didn't work. The new one costs money. Grumble.

. I had to reinstall the drivers for my Wacom touchpad.

And that's about it. Not bad, all things considered.

Now, the thing I dread is doing this to my home computer, which has a perfectly good Teac USB DAC/amplifier thing for which Teac hasn't released new drivers. So I'll have to wait on that.